Sunday, December 12, 2010

SHORT SCIENCE LESSON: ENERGY!

A Short Science Lesson:   The Big Bang happened.  All that energy in one humongous mass!   Our sun is the source of our energy and gravity.  

The more the mass of something, the more gravity it contains, so the earth has gravity, too, and so does our moon, but one-sixth less because it's about one-sixth the size of Earth.  Then Isaac Newton came along and sorted it out for us--the mechanics of energy and its relationship to gravity. 


The cycle of energy.  As you know, energy comes from the sun.  We use our own physical energy to do the work of preparing soil and planting seeds.  The sun gives energy to the plants to grow -- food from plants is later eaten and gives us energy -- our muscles use this energy to do work, to take care of the garden -- our muscles also use this energy to make tools to help us do our work -- we plant seeds the next year -- and so the cycle of energy repeats itself.  Same energy, over and over, in different forms and different shapes.

We usually think of energy as:  
(1)  The energy we get from the food we eat as well as the way our bodies feel -- ranging between having no energy and having lots of energy.  
(2)  The energy it takes to fuel our cars, to heat our homes, etc.  
Actually, everything, and I mean everything, has energy.  Even a rock?  Even a book?  Even a pie pan?  Yes, yes, and yes.  Because the definition of "energy" is simply "the ability to do work."  

To prove it, think about this:  If a tennis ball falls off the table and lands on your foot, does it hurt?  Probably not much.  However, if a bowling ball falls off the table and hits your foot, that will definitely hurt!  Why?  Because the bowling ball did a lot of work on your foot, but the tennis ball only did a little.  (In this case, unfortunately, the "work" turned out to be about doing injury to your foot!)